A person who eats meat virtually to the exclusion of vegetables. The meatatarian often claims to be conserving veggies for those who would actually eat them, and keeps the veggies out of the waste stream, helping the environment, or keeping produce costs down.
Waiter: "What can I get you?"
Mary: "A cheeseburger delux, hold the lettuce, tomato, coleslaw, and pickle."
Waiter: "So you just want the burger and fries."
Mary: "Yep, I'm a meatatarian."